Control system for a pipeline having a plurality of branches



Nov. 23, 1965 E. A. ERIcsoN CONTROL SYSTEM FOR A PIPELINE HAVING APLURALITY OF BRANCHES Original Filed Deo. 22, 1961 ./wvf Y 2 1 1 E L .NN m oH\J4 o 4 I RO R 3 8 6 6 7 2 L OS q 8 8 8 8 T O B :r NC T 2 w ER T wVE A Mw. 8 u m 8 u G A I l T 9 5 Il w1 I. F 5 1 u 9\/\ E N I|I| R W0 E YA9 B L N I N E N E u. O WO W0 WO 9 O f e D G n w I k6 N S0 I SO 3 Q o os o e o L B L 8 L 8 F 9 C C C FO H 4 .A O C H w n n E E E mo u O G G G UI ON O ON 5 ON A N2 B NA 5 NA 5 NA L Rl H0 8 HO 8 HO O 9 :i: I C C C H mE b E w E G G G No N0 N0 M M M C C c I 2 3 F 8. F 8 F 8 N F 8 F 8 F 8 u0 4v o@ AV 4v o T T T T Il III. I ME WE WE E 0 SO PSO PSO S n \I 8 PE EE E G II m 0R OR OR R 2 8 0 a E. E. E Il 8 w Vl. V2 V3 I L L 0 LO O F mW AN AN .NN 4 .p B V V OIIaU B United States Patent O 3,219,050 CNTROLSYSTEM FUR A. PIPELINE HAVING A PLURALITY F RANCl-IES Ernest A. Ericson,Channelview, Tex., assigner, by mesne assignments, to Esso Research andEngineering Company, Elizabeth, NJ., a corporation of Delaware Originalapplication Dec. 22, 1961, Ser. No. 161,558, now Patent No. 3,158,888,dated Dec. 1, 1964. Divided and this application Mar. 2, 1964, Ser. No.348,595

6 Claims. (Cl. 137-112.)

This is a division of copending application Serial No. 161,558, -l-edDecember 22, `1961, now Patent No. 3,158,888.

The present invention relates to the launching of pipeline Scrapers (orpigs). More particularly, the present invention deals with the launchingof pipeline pigs from a magazine whereby a plurality of pigs may bestored and from whence the pigs may be injected into a pipeline withoutinterrupting the iiow of fluid through said pipeline, allowingcontinuous flow of fluid through the launching mechanism at all times,and allowing the selective introduction of one or a plurality ofScrapers at predetermined time intervals without interrupting the ilowof fluid through the launching mechanism.

In the operation of product or crude oil pipelines, or of any otherpipeline which is susceptible to the deposition of surface contaminants,it is desirable at intervals to pass a scraper or pig through saidpipeline in order to remove materials which have deposited on the innersurface yof the pipes. One of the more desirable forms of pipelineScrapers is made up of a spherical or spheroidal flexible pig which maybe filled with a fluid such as a liquid to a diameter of about 1%greater than the inside diameter of the pipeline and then forced throughthe pipeline by the pressure of the flowing stream. The presentinvention relates to a control system whereby the launching andreceiving of spherical pigs may be used as a means for controlling theconduit through which the fluid is passed, thus enabling automaticshifting of the fluid stream from one storage tank to another whenutilizing pigs as interface barriers in pumping slugs of differentfluids through the same pipeline.

In order better to understand the nature of the present invention,attention is directed to the drawings wherein:

FIG. l is a schematic diagram of an automatic control system for usewith pig launching apparatus; and

FIG. 2 is a representation of the simplified control board used with thecontrol system of FIG. 1,

By reference to FIG. 1, the control system of the present invention canbe seen to comprise a plurality of valves 807, 809 and 811, each circuitmeans being identical to the other circuit means and operating a singlevalve. Taking the circuit means for controlling valve 807 as exemplary,it can be seen to comprise first electrically conductive means 824(which terminates in contacts at 025 and 835), second electricallyconductive means 827, and third electrically conductive means 837; firstswitch means 825 for selectively connecting either of said secondelectrically conductive means 827 and said third electrically conductivemeans 837 to said first electrically conductive means 824; fourthelectrically conductive means 829, 831, 832 for energizing a valveactuator shown as the solenoid 833; second switch means 828 forselectively connecting the iirst electrically conductive conductivemeans 827 and said third electrically conductive means 837 to saidfourth electrically conductive means 829, 831, 832. A third switch means830 is interposed in the fourth electrically conductive meansintermediate the portions 829 and 831, and is operative for selectivelyinterrupting the ilow of electricity through the fourth electricallyconductive means.

3,219,050 Patented Nov. 23, 1965 It will be noted that the means 870 isprovided for moving all of said first switch means 826, 850, and 860 inconcert from a first position connecting each of said first and saidsecond electrically conductive means to a second position connectingeach of said first and said third electrically conductive means. It willalso be noted that in each of said circuit means (as exempliiied by thecircuit means controlling valve 807) shortcircuiting means throughswitch 881 are provided for bypassing the first, second and third switchmeans for selectively connecting the rst electrically conductive means824 with the fourth electrically conductive means 829, 831, 832 forenergizing the solenoid 833.

Referring now to FlG. 1, wherein a schematic diagram of an automaticsystem responsive to the launching and receiving of spherical pigs isset forth, the pig launching mechanism is designated by the numeral 800,comprising a basket means 801, which is moved by a motor 802 having acontrol circuit such that a revolution of the basket is automaticallyaccomplished each time the motor is energized, such circuits being wellknown in the art. A line 803 is shown through which the pig 804 may passin either direction. For the purpose of explanation of the figure, itwill be assumed that the pig is passing toward the launching andreceiving mechanism 800 through 803, with the flowing stream beingdischarged through line 805 for storage in a tank fed by line 806controlled by valve 807. Alternate storage tanks are served by line 808,controlled by valve 809, and line 810, controlled by valve 811. Thecontrol valves are shown for the purpose of explanation as beingsolenoid valves normally closed but opened by the passage of currentthrough the solenoid control element. It is to be understood thatpneumatic control valves or electronic control valves could be used forthis purpose. The passage of the pig 804 through the line 803, in eitherdirection, is sensed by means 812 which may comprise a spring-loadedmechanical switch responsive to a probe extending into the pipeline(such as that shown in application Serial No. 818,723 filed by R. H.Pfrehm now Patent No. 3,021,703), which is tripped by the passage bysphere 804 through the line, or may comprise a reply switch with aholding circuit which is energized by passage of the pig and which willmaintain a current flow through the electrical lines 820 and 821,hereinafter more fully described, until the current through those linesis broken by a switch, at which time the holding circuit releases therelay and the sensing means 812 is again ready for service. Such switchmeans are well known in the electrical arts. Preferably, the relay andholding circuit type of sensing means will be employed. The schematicdiagram of FIG. 1 illustrates the condition of the circuit when theliquid is flowing through line 803 and is discharged for storage vialine 805 into the tankage served by line 806, valve 807 being maintainedin the open position. Valves 809 and 811 are in the closed positionduring this type of operation. Assuming that a type of hydrocarbon orother liquid which is intended yfor storage in tankage other than thatsupplied by line 806, for example, intended for storage by way of line808, is passing through the line 803, the pig 804 being positioned atthe interface between the two diverse types of fluid flowing through theline. It is the functon of the control circuit shown to enable theoperator to preset the control system to make the tankage switch uponarrival of the interface, as indicated by the passage of the pig 804through the line, and thereby to cause the tankage switch to be madeautomatically without the delay which would be inherent in manualcon-trol. As the control circuit is set up in FIG. l, power is suppliedby lines L1 and L2. Line L1 is directed into the control board by way ofline 824, and the current is passed into valve 807 by way of line 824,line 825, switch 826, line 827, switch 828, line 829, switch 330, line831 and line 832. The solenoid 833 of valve 807 is connected by line L2by way of line 834 so that as the circuit is set up, current flowsthrough solenoid 833 is order to maintain the valve S07 in the openposition. Note that no current flows through the solenoid coils of theother valves during this period of time, and, therefore, they remain inthe normally closed position.

Returning now to switch 826, it will be seen that switch 826, along withswitches 840, 850 and S60 are mounted on a bar 870 which passes througha coil 830. This type of solenoid switch is well known in the art and ismaintained in the position shown in FIG. 1 by a spring, not shown. Uponpassage of a current through the coil 88h, the switches mounted upon bar870 are moved to a second position which is indicated by the opencontacts below the contacts being closed by the switches 826, 850 and865B.

Upon energization of the coil 880 by passage of the pig through theline, the switches will be moved into their second position, and theline S06, controlled by valve 807, will be automatically shut off. Thisis accomplished as will be seen by advertence to FIG. l, by followingthe path of line L1 through line 824, line 835, switch 826, and line837, at which point the switch 828 is open and no current can ow fromline L1.

Referring now to the control system for valve S09, which is in theclosed position and which is to be opened by the passage of pig 804, itis seen that switch 851 is in the open position with respect to line L1when the switch 35() is in its first position, and, therefore, thesolenoid valve 809 is maintained in the closed position. Upon themovement of switch S50 to the second position, however, current isallowed to ow through line 824, line 852, switch S50, line 853, switch851, line 854, switch S55, line 856 and line 857 into the solenoid 858of valve 869. The solenoid 858 is connected to line L2 by way of line834, as in the case of valve 807. Therefore, upon movement of the switchinto the second position, current will ow through valve 809 and willcause the opening of that valve so that the fluid may ow through line80S at the same time the line 806 is being shut down.

Referring now to valve 811 in line 810, which is in the closed positionduring the initial period and which is desired to be maintained in theclosed position after the movement of the switch into the secondposition, it is seen that line L1 is connected by way of line 824 andline 861, switch 860, and line 862 and is broken by switch 863 when theswitch 850 is in the first position. Upon passage of the switch 860 intothe second position, line L1 is connected by way of line 824, line S64,switch 860, line 365, switch 863, and line 866 and is broken by switch867. It is, therefore, seen that at neither position of switch 860 isthe valve 811 maintained in the open position.

After movement of the switches carried by the bar 87) into the secondposition, it becomes necessary to reset the switch before reception ofthe pig in another instance. In order to maintain the valve which hasbeen opened by the movement of the switches carried by bar 870 in theopen position during the reset period, it is necessary to maintain aflow of current through the solenoids controlling those valves. In theexample stated above, the valve 809 must be maintained in the openposition while the switches carried by bar 870 are returned into theirnormal positions. It is for this purpose that the reset open switches881, 882 and 883 have been provided. Switch 882 controls the valve 809and is placed in the closed position, designated open reset on thecontrol board, and current is passed from line L1 through line 824, line885, switch 882, line 886, line 857 and solenoid 85S with return beingmade by line 834 through line L2. The valves therefore are maintained inthe open position while the bar 870 is returned to its initial positionby opening switch 890, which breaks the ow of current through the coil88th and allows the return of the switches to their original position.At this point, the switch 851 may be turned to the open position andswitch 8&2 turned to the off position, and then, upon closing of theswitch 890, the valve 809 will remain open until the passage of a pigthrough the line, at which time it may be automatically closed.

It should be noted that before the operation of the reset switch 899,the valves which had been automatically closed must be maintained in theclosed position by turning the switches (for example, switch 823) intothe closed position on the control board, otherwise these Valves wouldbe reopened upon return of the switches (for example,'switch 826) intothe original position.

lt is thus seen that the switching of the various tanks or of thevarious lines may automatically be accomplished by the arrival of thepig, by setting the switches in the control system in a predeterminedpattern in order to `accomplish the desired result. This will be morefully discussed hereinafter in connection with FIG. 2.

The system of operating the valves automatically, as set forth above inconnection with the reception of pig 804 by the launching and receivingmechanism 890 is as fully applicable to the launching of the pig as itis to the receiving thereof. In this case, the basket 801 may be rotatedby motor 802, actauted by the closing of switch 900 for release of a pigwhich in passing by sensing means 812 will cause the opening and closingof the valves as hereinabove set forth, thereby automatically changingthe nature of the stream Iiowing through the pipeline, minimizing thelosses or admixture of products. Similarly, the portion of the streamwhich would represent an admixture of impure products may be maintainedwithin a confined space by launching a first pig which would operate theswitching of the valves and cause a change in the nature of the stream.The stream ahead of the pig would be substantially pure, while thestream behind the pig would contain .an adrnixture of products. It wouldthen be feasible, after the passage of a time period sufficient to flushout of the line most of the preceding products, to operate the piglauncher through another launching cycle, and a second pig would thenprecede vsubstantially pure product of the second nature. By launchingthe two pigs before operating the reset rnechanism of the controlsystem, the valves would not be again operated by passage of the secondpig, and good control of the system could thereby be attained.

Particularly in connection with the reception of a pig by the launchingmechanism, warning devices are provided to indicate to the operator thatthe switch has been moved from its first to its second position and,therefore, requires reset before it can be depended upon for a secondcycle of operations. The warning light 910 and horn 912 are connected inseries by way of lines L2, line 914 and line 916 through switch 840.Upon movement of the bar 870 into its second position, the switch 84.0closes the circuit and causes the warning light and horn to be actuated,thereby indicating to the operator that the switch requires reset beforeuse in a subsequent cycle.

Referring now to FIG. 2, the simplicity of operation of the presentcontrol system is shown by reference to the control board `and positionsof the switches as has been indicated thereon. A series of threeswitches is provided for each valve, corresponding, for example, withrespect to valve 807, to the switches 881, 83d, and 82S. The valve 807is maintained in the opening position prior to passing of the pig bymoving the switch S28 into the open position. As has been shownhereinabove, the switch maintains a current through the solenoid 33 andkeeps the valve in the open position. Since the position of the valve isdesired to be changed by passage of the pig through the line, the switch830 is maintained in thc change position, corresponding to the positionshown in FIG. 1. The open reset switch is maintained in the off positionat all times except during the reset operation. As has been shownhereinabove, at the time that the pig 804 passes through the line 803,the position of the valve will be changed from open to closed. At thattime the warning device will indicate to the operator that the changehas taken place, and the switch 828 will be moved to indicate closed,which is the desired new position. With respect to valve 809, which isclosed initially but desired to be open, the switch 851 is initiallyturned to the closed position, indicating the desired state of affairsin the initial case. The change switch S55 is moved to the changeposition since it is desired to have the position of the valve changedfrom closed to open. The open reset switch is, as stated above,maintained in the off poition. Upon passage of the pig through thelines, the valve automatically will be open, ,and will be maintainedopen by moving the open reset switch into the open reset position,moving the switch 851 into the open position, and activating the resetswitch 890, at which time the switches will be moved into the normalposition, and thereafter the open reset switch will be returned to theoff position.

Referring now to the control of valve 811, which it desired to maintainin the closed position both before and after the passage of the pigthrough the line S03, the switch 863 is in the closed position, andswitch 867 is placed in the no change position since no changes aredesired in the positioning of the valve. The open reset switch ismaintained in the off position throughout.

Therefore, it is seen that by a simple setting on the control boardprior to passage of the interface, as sensed by passage of the pig, theproducts passing through the pipeline may automatically be switched intothe desired storage tanks (or from the desired storage tanks if the pigis being launched from mechanism 800).

If the mechanism 800 is to be used for launching, the switch 900 ismoved to the launch position, which causes rotation of the basket 801Athrough an arc of 180. The switches being preset, the y*sequencefollowing the launching of the pig occurs automatically, as set forthhereinabove with respect to the receipt of a pig, and the warning signalwill indicate that the change has taken place. At this point, the piglaunch switch may be returned to the off position, at which time thecontrol system at motor S02 will reset for another 180 rotation. Thelaunch switch will then again be actuated in order to return the basketto its initial position, and upon the re turn of the launch switch tothe off position for the second time, the pig launcher will then beready for launching a second pig. The reset switch will then be actuatedas set forth hereinabove, the valves which have been automaticallyclosed being previously changed to the closed position by activation ofthe valves 828, 851 or 863, respectively, or being controlled to remainopen by movement of the switches 828, 851, and 863 to the open positionas desired.

Having disclosed in detail the substance of the present invention andthe objects thereof, including the preferred embodiment, what is desiredto be protected by Letters Patent should be determined not by thespecific examples herein given, but only by the subject matter definedin the appended claims.

I claim:

1. A control system for selectively operating a plurality of valves,each having a valve actuator, which comprises a plurality of circuitmeans, each circuit means comprising first, second, and thirdelectrically conductive tmeans, first switch means for selectivelyconnecting either of said second and said third electrically conductivemeans to said first electrically conductive means,

fourth electrically conductive means `for energizing a single valveactuator,

second switch means for selectively `connecting either of said secondand third electrically conductive means to said fourth electricallyconductive means,

third switch means interposed in said fourth electrically conductivemeans for selectively interrupting the flow of electricity therethrough,

and means for moving all of said first switch means in concert from afirst position connecting said first and said second electricallyconductive means to a second position connecting said first and saidthird electrically conductive means.

2. A control system in accordance with claim 1 further comprising, ineach of said circuit means, short-circuit'ing means bypassing saidIfirst, second and third switch means for selectively connecting saidfirst and said .fourth electrically conductive means.

3. A system comprising a pipeline through which a pig may be passed anda plurality of pipes communicating with said pipeline, each of saidpipes -being controlled by a solenoid valve interposed therein,

a plurality of circuit means, one for each solenoid valve,

each circuit means comprising first, second and third electricallyconductive means,

first switch means for selectively connecting either of said second andsaid third electrically conductive means to said first electrical-lyconductive means,

fourth electrically conductive means for energizing a single solenoidvalve,

second switch means for selectively connecting either of said second andsaid third electrically conductive means to said fourth electricallyconductive means,

third switch means interposed in said fourth electrically conductivemeans for selectively interrupting the flow of electricity therethrough,

sensing means for sensing the passage of a pig past a predeterminedpoint in said pipeline,

and means responsive to said sensing means for moving `all of said firstswitch means in concert from a first position lconnecting said :firstand said second -electrically conductive means to a second positionconnecting said first and said third electrically conductive means.

4. A control system in accordance with claim 3 further comprising, ineach of said circuit means, short-circuiting means bypassing said first,second and third switch means for selectively connecting said first andsaid fourth electrically conductive means.

S. A system in accordance with :claim 4 wherein there are at least threecircuit means.

'6. A control system in accordance with claim 5 further comprising alarmmeans actuated in response to said sensing means.

References Cited by the Examiner UNITED STATES PATENTS 2,965,1141'2/1960 Harden 137--268 2,965,1125 -12/1960 Osborne et al 1372683,089,030 5/1963A Scherbatskoy 137-2 XR M. CARY NELSON, PrimaryExaminer.

MARTIN P. SCHWADRON, Examiner.

3. A SYSTEM COMPRISING A PIPELINE THROUGH WHICH A PIG MAY BE PASSED ANDA PLURALITY OF PIPES COMMUNICATING WITH SAID PIPELINE, EACH OF SAID PIPEBEING CONTROLLED BY A SOLENOID VALVE INTERPOSED THEREIN, A PLURALITY OFCIRCUIT MEANS, ONE FOR EACH SOLENOID VALVE, EACH CIRCUIT MEANSCOMPRISING FIRST, SECOND AND THIRD ELECTRICALLY CONDUCTIVE MEANS, FIRSTSWITCH MEANS FOR SELECTIVELY CONNECTING EITHER OF SAID SECOND AND SAIDTHIRD ELECTICALLY CONDUCTIVE MEANS TO SAID FIRST ELECTRICALLY CONDUCTIVEMEANS, FOURTH ELECTRICALLY CONDUCTIVE MEANS FOR ENERGIZING A SINGLESOLENOID VALVE, SECOND SWITCH MEANS FOR SELECTIVELY CONNECTING EITHER OFSAID SECOND AND SAID THIRD ELECTRICALLY CONDUCTIVE MEANS TO SAID FOURTHELECTRICALLY CONDUCTIVE MEANS, THIRD SWITCH MEANS INTERPOSED IN SAIDFOURTH ELECTRICALLY CONDUCTIVE MEANS FOR SELECTIVELY INTERRUPTING THEFLOW OF ELECTRICALLY THERETHROUGH, SENSING MEANS FOR SENSING THE PASSAGEOF A PIG PAST A PREDETERMINED POINT IN SAID PIPELINE, AND MEANSRESPONSIVE TO SAID SENSING MEANS FOR MOVING ALL OF SAID FIRST SWITCHMEANS IN CONCERT FROM A FIRST POSITION CONNECTING SAID FIRST AND SAIDSECOND ELECTRICALLY CONDUCTIVE MEANS TO A SECOND POSITION CONNECTINGSAID FIRST AND SAID THIRD ELECTRICALLY CONDUCTIVE MEANS.